CVE-2025-4883
📋 TL;DR
A critical stack-based buffer overflow vulnerability in D-Link DI-8100 routers allows remote attackers to execute arbitrary code by manipulating parameters on the connection limit page. This affects all systems running the vulnerable firmware version, potentially giving attackers full control of the device. The vulnerability is remotely exploitable without authentication.
💻 Affected Systems
- D-Link DI-8100
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution leading to complete device compromise, lateral movement into internal networks, and persistent backdoor installation.
Likely Case
Device takeover leading to network traffic interception, credential theft, and use as a pivot point for further attacks.
If Mitigated
Limited impact if device is behind strict firewall rules and network segmentation, though device integrity remains compromised.
🎯 Exploit Status
Exploit details are publicly available on GitHub. The vulnerability requires no authentication and has straightforward exploitation.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Unknown
Vendor Advisory: https://www.dlink.com/
Restart Required: Yes
Instructions:
1. Check D-Link website for firmware updates. 2. Download latest firmware. 3. Access router admin interface. 4. Navigate to firmware update section. 5. Upload and apply new firmware. 6. Reboot device.
🔧 Temporary Workarounds
Network Isolation
allPlace DI-8100 behind firewall with strict inbound rules, blocking access to management interface from untrusted networks.
Access Control
allRestrict access to the router's management interface using IP whitelisting or VPN access only.
🧯 If You Can't Patch
- Immediately isolate the device from internet-facing networks
- Implement strict network segmentation to limit potential lateral movement
🔍 How to Verify
Check if Vulnerable:
Check firmware version in router web interface under System > Firmware. If version is 16.07.26A1, device is vulnerable.Check Version:
Check via web interface or SSH if enabled: show versionVerify Fix Applied:
After firmware update, verify version is no longer 16.07.26A1. Test connection limit page functionality.📡 Detection & Monitoring
Log Indicators:
- Unusual access to /ctxz.asp
- Multiple failed buffer overflow attempts
- Unexpected device reboots
Network Indicators:
- Unusual traffic patterns from router
- Suspicious outbound connections from router
- Port scanning originating from router
SIEM Query:
source="router_logs" AND (uri="/ctxz.asp" OR message="buffer overflow")🔗 References
- https://github.com/Yhuanhuan01/DI-8100_Vulnerability_Report/blob/main/DI-8100-Vulnerability_Report_ctxz.md
- https://vuldb.com/?ctiid.309436
- https://vuldb.com/?id.309436
- https://vuldb.com/?submit.576392
- https://www.dlink.com/
- https://github.com/Yhuanhuan01/DI-8100_Vulnerability_Report/blob/main/DI-8100-Vulnerability_Report_ctxz.md
